Tewonim-g-augek



t 4o l' i UNITED STATES PATENT OFFICE.

WILLIAM VA. CLARK, OF BETHANY, CONNECTICUT.

TENONIN'Gr-AUGER.

Specification of Letters Patent No. 28,653, dated June 12, 1860.

T 0 all whom it may concern:

Be it known that I, VILLIAM A. CLARK, of Bethany, in New Haven county,State of Connecticut, have invented a new and useful Improvement inAdjustable Hollow Augers; and I do hereby declare that the following isa full and exact description thereof.

It is essential to the successful working of a hollow auger, that thetenon formed by it should be of the exact size adapted for the boreformed by its corresponding augerbit. As hollow-angers are now commonlymade, this is found difficult, and often impracticable. Diierences insize, of a greater or less degree, between the barrel of thehollow-auger and the auger-bit it is adapted to fit, exist; though themanufacturer intends them to be of the same size. And when of the samesize as originally made, the constant tendency of the frictionconsequent upon their use, is to create dissimilarity, by making thebarrel of the hollow-auger larger, and the diameter of the auger-bitsmaller.

My invention consists in an improved mode of remedying these defects, bymaking the barrel of the hollow-auger adjustable, and enabling theoperator, though having but a single auger, to adapt the size of thetenon (within a reasonable limit) to the bore of his auger-bits. It willthus be found of especial convenience where, as in the repairing of awagon wheel, the wheelwright has to fit one or more tenons to a borealready made, and for which he may have no auger of the size adapted toform a suitable tenon.

I use the term improved mode of adjusting the barrel, for I am awarethat the idea itself is not now new, as one mode of accomplishng thisresult is described in the specifications of Letters Patent issued tome, dated July 12, 1859.

My present improvement consists in casting about one third of the barrelof the auger in two parts, in such form as that, being united, they makea perfect` barrel with its interior surfaces such, that longitudinallines drawn thereon from the opening of the barrel to its terminus, areat all times parallel to each other within the entire limit of theadjustability of the instrument; and at the same time it is, in strengthand capacity to resist torsional pressure, equal to the solid barreledhollow-auger.

The accompanying drawings are referred tc, and made part of thisspecification, as explanatory of my said improvement.

The auger is cast in two parts, Figure I showing one part thereof, Abeing that portion of the barrel which is cast as in the commonhollow-auger, with the shank E, and B representing that portion of theauger, being the section of one half thereof, to which the correspondingsection C, as represented in Fig. II, is designed to be fitted.

D marks the point of division, upon the barrel of the auger, where thesesections begin. Both sections are furnished with flanges, (I-I H) inwhich are the fitting screw-holes a, a, and the grooves b, b,hereinafter more particularly described. The barrel or bore of the augeris so constructed, that when these two corresponding `sections arefitted, and brought as closely in contact as possible by the screwsfitting into the holes a, a, that portion of the barrel represented byA, and extending from the terminus at the shank end to the point ofdivision D, is as large as the largest tenon for which the instrument isdesigned; while that portion of the barrel between the two sections Band C, and extending from the opening of the barrel to the point ofdivision D, is as small as the smallest tenon for which the instrumentis adapted; and to the extent that this portion of the barrel, while thetwo sections are thus closely fitted together, differs in size from theother portion of the barrel of the auger, its diameter in the line ofdivision between the two sections, is greater than its diameter in aline drawn at right angles to such line of division. The extent to whichsuch difference in diameter can successfully be carried, is the onlylimit to the capacity of the auger, as applied to the varying sizes ofthe tenons to be formed.

In practice I have foundit convenient to make that portion of the barrelembraced between the two sections of such size, that when the sectionsare brought as closely as possible in contact for making the smallesttenon within the capacity of the instrument, the diameter of theaperture in the line of the section, exceeds the diameter of a linedrawn at right angles to it, by about onesixteenth of an inch. It is notessential, however, that this difference in diameter should extendthrough the entire length of the barrel, between these two sections. The

same object will be attained, if a sufficient portion thereof, at andfrom its opening, to give the bearing and form of the tenon, is thusconstructed ;-and then the remainder of this portion of the barrel maybe of the same size and form as in A. Upon the line of division of eachof these two sections, and at about one-third the distance from theouter edge of the barrel to the outer edge of the lip, and upon eitherside of the barrel, a half section of a triangular wedge-shaped grooveZ2, b, is made, having its largest diameter at the lip, and graduallydecreasing toward and u to the line of division between the two sectionsat D. These grooves are of such size and form as that, when the twosections are brought together as closely as possible for forming a tenonof the smallest size within the capacity of the instrument,

the two wedges, one of which is representedl in Fig. III, will exactlyfit into the grooves, with the larger end of the wedges on a line andflush with the outer surface of the face of the auger. When now, the twosections are brought together and fastened in contact by means of theset screws at a, with upper surface of the larger' end of the wedgesflush with the outer surface of the face of the auger, the instrument isadapted to form a tenon of the smallest size within its capacity. Whenit is. desired to increase the size of the tenon, the set screws areloosened, and the wedges driven down toward the shank end of the augerto a greater or less extent, in proportion to the degree of variation ofsize required, and the set screws again firmly iiXed in place. Theinstrument may thus be varied in size within the limit of itsadjustability, to suit the size of different auger-bits, and yet,throughout the entire limit of the variation, the inner surfaces of thebarrel remain parallel with each other, and there is no more strain ortendency to break, than in the solid-barreled hollow-auger.

The other figures upon the drawing eX- plain themselves. Fig. IV,representing a sectional view of the auger, and Fig. V, a view of theauger as completed, with the cutters E, as in the ordinaryhollow-augers.

Vhat I claim as my invention, and desire to secure by Letters Patent,is-

An adjustable hollow-auger, having the longitudinal lines of theperiphery of the inner surfaces of the barrel at all times parallel toeach other, within the entire limit of the adjustability of theinstrument, constructed substantially as above described.

WM. A. CLARK.

In presence of- JNo. S. BEACH, DENNIS KIMBERLY.

